循环荷载下红层泥岩土累积变形特性

 针对红层泥岩土这种特殊的粒类材料，通过动三轴试验研究其在循环荷载下的累积变形特性。在动荷载不超过临界动应力条件下，红层泥岩土累积应变随循环次数的变化有一定规律性：应变在初期是快速增长，随着循环次数的增加，应变增幅减缓，最终达到稳定，且变形主要发生在前1 000次的循环阶段。基于动三轴试验结果，并考虑土的类型、应力状态、物理性质和循环次数等主要影响因素，提出了一个计算红层泥岩土累积变形的模型。该模型不仅能反映动、静偏应力和静强度的影响，还考虑了围压对累积应变的影响，能较好地反映累积应变的发展规律，而且模型参数具有明确的物理意义。通过达成线红层泥岩路基现场激振试验，验证了该模型的有效性和实用性。

Cumulative Deformation Properties of Red Mudstone Soils under Cyclic Loading

The properties of cumulative deformation of  red mudstone soils, a special grain material, under cyclic loading are investigated through dynamic triaxial tests. When dynamic load is below the critical dynamic stress, the variation of cumulative strain of red-mudstone soils has its own laws: cumulative strain grows rapidly in the early stage; with the increase of load cycles, the increasing rate of strain slows down, and the strain finally reaches stable. At the same time, most of the deformation occurs before the first 1 000 cycles. On the basis of dynamic triaxial test results and in consideration of main factors such as soil type, soil’s stress state, soil''s physical state and the number of load cycles, a model to calculate the cumulative strain of red-mudstone soils subjected to cyclic loading is put forward. This model can reflect the influences of dynamic deviatoric stress, static deviatoric stress, static strength and confining pressure. Meanwhile, the model parameters have clear physical meaning and are easy to determine. The validity and practicality of this model is verified through field excitation tests on red mudstone subgrade of Dazhou-Chengdu Highway.